In U.S. Pat. No. 5,448,582, issued Sep. 5, 1995, entitled "Optical Sources Having a Strongly Scattering Gain Medium Providing Laser-Like Action", the inventor disclosed a multi-phase gain medium including an emission phase (such as dye molecules) and a scattering phase (such as TiO.sub.2). A third, matrix phase may also be provided in some embodiments. Suitable materials for the matrix phase include solvents, glasses and polymers. The gain medium is shown to provide a laser-like spectral linewidth collapse above a certain pump pulse energy. The gain medium is disclosed to be suitable for inclusion within glass and polymer substrate materials.
Recently there has been development in the field of miniaturized diagnostic testing apparatus, such as miniaturized capillary electrophoresis apparatus. One known approach uses photolithographic techniques to form sub-millimeter size channels and wells within a surface of a glass substrate. Fine metal electrodes are used to generate electric fields to move a fluid of interest through desired channels. Fluorescent markers can be added to the fluid which, when illuminated with light of certain wavelengths, emits a characteristic spectra. Photodetectors can then be used to detect the emission.
More particularly, the use of glass and plastic based microstructures has created a new field based on the miniaturization of bioanalytical processes. This includes clinical diagnostic applications, fabrication of oligonucleotide arrays and the electrophoretic separation of bio-molecules. Such microchip-based analytical systems may manipulate fluids using electro-kinetic, centrifugal and other transport mechanisms, and often use absorption and fluorescence techniques to determine and identify product species and sequences.
The use of such absorption and fluorescence techniques typically requires a precisely tuned narrow band optical pump source, such as a laser. If a wide variety of wavelengths are required a tuneable dye laser may be used. As can be appreciated, the use of dye lasers is typically less than desirable due to the initial cost, the recurring costs of upkeep and maintenance, and the required use of fluids, pumps and plumbing.